Magnetic plug adapter



Jan. 9, 1968 c; T. WRIGHT 3,363,214

MAGNETIC PLUG ADAPTER Filed Jan. 21, 1966 54 58 56 50 INVENTOR. /4aCHARLES T. WRIGHT ATTORNEYS v United States Patent 3,363,214 MAGNETICPLUG ADAPTER Charles T. Wright, 26 Woodlawn Place, Longmeadow, Mass.01106 Filed Jan. 21, 1966, Ser. No. 522,256 12 Claims. (Cl. 339-42)ABSTRACT OF THE DISCLOSURE An adapter having plugs at one end to bereceived in the conventional baseboard sockets is provided with socketterminals on the other end which taper to receive, in one embodiment, asecond adapter having tapered contacts on one end and sockets on theother end to receive the prongs of a conventional plug. A magnet isdisposed in each of the mating faces of the two adapters and the holdingstrength thereof is such as to permit separation between the adaptersrather than between the first named adapter and the receptacle. Sincethe magnets are in the form of bars each having a north and a south polethe connection between the two adapters is polarized. In the secondembodiment, a connection to the wires of a cable are substituted for thesockets of the second adapter. The material of the bodies of bothadapters and of the plug may be of a non-conductive paramagneticmaterial.

This invention relates to improvements in electrical connectors anddeals more particularly with novel breakaway electrical connectors forcoupling flexible electrical conductors with electrical socket elements.

Most detachable flexible conductor extension circuits employ connectorshaving diverse mating coupling parts such as a socket receptacle and amating plugging element. Common among these connectors is the so-calledbaseboard outlet or socket and mating male spaced pronged plug.Connectors of this type are generally designed to detach or separatewhen a straight pull or force is exerted either directly upon the plug,or upon the flexible conductor associated with it. However, suchconnectors generally tend to hold fast when a pulling force, or thrustis exerted even slightly laterally relative to the plugging element.

The failure of such couplings to release upon the applications of alateral force has been at least in part responsible for the injuriesthat frequently result from tripping accidents in both 'home andindustry involving electrical extensions circuits. Often times a fallmay be avoided or the severity of the resulting fall injury may bereduced if the electrical coupling releases when the individuals footbecomes caught upon the electrical extension.

The careless disconnecting of home electrical appliances is a frequentsource of appliance failure. Many persons frequently resort to thesimple expedient of pulling upon an appliance cord to disengage a plugfrom an electrical outlet. Such practice often results in damage to theappliance, or to the electrical outlet when the mating coupling partsfail to readily disengage.

Accordingly, it is the primary object of the present invention toprovide a breakaway electrical connector for coupling a flexibleelectrical conductor with an electrical socket element which willreadily disengage when a disengaging force is applied to the conductorin a direction generally away from the socket element.

3,363,214 Patented Jan. 9, 1968 Another object of the invention is toprovide a breakaway adapter attachment for coupling an electricalextension circuit to an existing electrical socket element.

A further object of the invention is to provide a breakaway adapterattachment for converting a conventional electrical coupling havingdiverse mating parts to a breakaway coupling.

The drawing shows preferred embodiments of the invention and suchembodiments will be described, but it will be understood that 'variouschanges may be made from the constructions disclosed, and that thedrawing and description are not to be construed as defining or limitingthe scope of the invention, the claims forming a part of thisspecification being relied upon for that purpose.

Of the drawing:

FIG. 1 is a perspective view of an electrical connector embodying thepresent invention, the adapter and attachment parts of the connectorbeing shown spaced apart.

FIG. 2 is a sectional view of the connector of FIG. 1 taken along thelines 22 of FIG. 1 and showing the parts of the connector spaced apart,a conventional male plug being shown in phantom in position relativethereto.

FIG. 3 is an end view of the adapter part of the connector of FIG. 1taken along the line 3--3 of FIG. 2.

FIG. 4 is an end view of the attachment part of FIG. 1 taken along theline 44 of FIG. 3.

FIG. 5 is a half-sectional view showing a modified form of theattachment part of FIG. 1 and FIG. 2.

FIG. 6 is a sectional view of the attachment part of FIG. 5 taken alongthe line 6-6 of FIG. 5.

Referring in detail to the drawings, and particularly to FIGS. 1 and 2,an electrical connector made in accordance with one form of theinvention is illustrated and designated generally by the referencenumeral 10. The connector 10 generally comprises a first component oradapter 12 for connection with an electrical socket element not shownand a. second component or attachment 14 adapted for electricalconnection with a flexible conductor 16. The adapter 12 and theattachment 14 are adapted for mutual engagement to provide a path ofelectrical current between the socket and the conductor or electricalcord 16. Engagement between the adapter 12 and the attachment 14 ismaintained by a connecting means which is adapted to permit mutualseparation therebetween when a disengaging force is applied to theconductor in any direction generally away from the socket. Thedisengaging force necessary to separate the attachment from the adapteris generally substantially less than the force necessary to separate theadapter from the socket element in which it is received.

The electrical connector of the present invention is particularly suitedfor use in coupling a flexible electrical conductor or cord with aconventional electrical outlet or socket of the so-called baseboard typewhich receives a mating two-pronged plug. The invention is illustratedwith reference to such application, however, it will be apparent that itis also applicable for use with other electrical coupling arrangements,such as jack plugs and sockets and coaxial cable connections and thelike, and such applications are contemplated within the scope of theinvention.

To facilitate the provision of a breakaway electrical ex tension circuitin association with an existing electrical socket without the necessityof rewiring or otherwise materially altering the existing socket, theadapter 12 is provided. The adapter may be made to accommodate one ormore electrical extension circuits, however, in the illustratedembodiment of the invention, the adapter is shown to comprise a bodyportion or housing 18 for accommodating a single electrical extensioncircuit. An electrically nonconductive material which is also preferablymagnetically permeable is used to make the housing 18 for a reason thatwill be hereinafter apparent. The housing may be made in sections andmay assume various forms but as shown it is a unitary structure moldedfrom a suitable plastic material having a generally cylindrical form andincluding a first face 20 and a second face 22.

At least one recess 24 is defined within the housing 18 for receiving anelectrical contact associated with the attachment 14 to be hereinafterdescribed but preferably two relatively shallow space-d apart socketrecesses 24, 24 are defined within the first face 20 generally divergingthereto.

For establishing electrical contact with the socket element orelectrical outlet and for providing a path of electrical current throughthe housing 18, at least one conducting element 26 is provided. In theillustrated embodiment of the invention there are two conductingelements 26, 26 at least partially disposed within the housing 18. Eachof the conducting elements 26 includes a terminal 28 preferably disposedwithin an associated recess 24, providing a means for establishingelectrical contact with the attachment 14. Each of the conductingelements 26 further includes a prong 30 projecting outwardly from thesecond face 22. In the embodiment shown the spaced apart aprallellyaligned prongs 30, 30 are adapted to be received in the receptacle of aconventional socket element or electrical outlet.

A first magnet 32 is preferably disposed within the housing 18 proximatethe first face 20 providing a means for maintaining engagement betweenthe adapter 12 and and the attachment 14 in a manner to be hereinafterfurther described.

To establish a path of electrical current between the adapter 12 and theconductor or electrical cord 16, the conductor attachment 14 isprovided. The attachment is adapted for engagement with the adapter 12and for electrical connection to the cord 16.'The attachment 14comprises a body portion or casing 34 having a configuration preferablygenerally similar to that of the housing 18. Like the housing 18 thecasing 34 is made from an electrically nonconductive material which isalso preferably magnetically permeable. The casing is preferablycylindrical and includes a third face 36 and a forth face 38. At leastone elongated inwardly extending receptacle 40 is defined by the casing34 normal to the fourth face 38 for receiving a male plugging elementassociated with the cord 16. However, in the illustrated form of theinvention two parallelly aligned spaced apart female receptacles areprovided for receiving the male prongs of a conventional plug 42associated with the cord 16.

A path of electrical current between the plug 42 and the adapter 12 isestablished by at least one contacting element 44. But'preferably and asshown, two such contacting elements are provided. Each'of the contactingelements 44 is preferably formed from a flat strip of electricallyconductive metal, such as a copper alloy and includes a generallyU-sha-ped end portion disposed within an associated receptacle 40 andsuitably bent to provide a leaf spring having a contact surface 45 formaking electrical contact with an associated prong on the plug 42.

Preferably each of the contacting elements 44 further 7 end of each ofthe contacts 46 is chamfered to complement at least a portion of anassociated recess 24 to facilitate ready removal thereform for a reasonthat will be hereafter apparent. To assure positive electrical contactbetween the contacts 46, 46 and the respectively. associated terminals28, 28 allowance may be made for a slight clearance between theassociated faces 20 and 36 when the contacts are in engagement with theterminals. It should be apparent from the foregoing description thateach of the conducting elements 26 cooperates with a respectivelyassociated contacting element 44 to form a conductive means forproviding a path of electrical current between a respectively associatedmale element 30 and the conductor 16.

A second magnet 48 similar to the first magnet 32 is preferably disposedwithin the casing 34 proximate the third face 36.

Connecting or securing means for maintaining engagement between theadapter 12 and the attachment 14 is provided by the cooperation of thefirst magnet 32 and the second magnet 48. The connecting means maycomprise one or more magnets and the configuration of the magnets mayvary. However, in the illustrated embodiment of the invention a pair ofbar magnets is shown.

The first magnet 32 and the second magnet 48 are respectively positionedwithin the adapter 12 and the attachment 14 so as to register when theattachment is brought into engagement with the adapter. The two magnetsare further arranged so that their flux paths link for mutual magneticattraction when the two parts of the device are brought into engagement.Thus, the magnetic field of the first magnet 32 coacts with the magneticfield of the second magnet 48 to mutually attract the adapter 12 and theattachment 14 with a force sufficient to maintain the two parts inengagement.

In the. illustrated form of the invention, bar magnets are employed andare respectively positioned in longitudinal alignment with the firstface 20 and the third face 36, as best shown in FIGS. 3-4. Since themating faces 20 and 36 are symmetrical, it should be apparent that thesefaces may be brought into mutual engagement in one of two possiblepositions. It should be further apparent that bar magnets havingopposite end poles arranged in' the position shown will cause the facesto be attracted to one another when they are brought into closeproximity in one possible assembly position and will cause repulsiontherebetween when assembly in the opposite position is attempted. Thismagnet arrangement advantageously facilitates the'rapid accurateconnection of polarized electrical circuits. 7

It should be further apparent that if each magnet is positioned with asingle pole thereof proximate a respec tively associated face, therespective parts may be arranged for mutual attraction in eitherpossible assembly position. Such arangement would be preferable whencircuit polarity is not a consideration.

A similar connection between the two parts of the coupling may beeffected by utilizing a magnet disposed within either of the connectorelements to attract a para magnetic material disposed within theopposite element.

When a magnetic connecting means is employed, the force required todisengage or separate the attachment from the adapter will be dependentupon the strength of the magnetic field. Thus, a connecting means may bepro-' contacts 46, 46 and of the generally complementarycontact-receiving recess facilitates ready removal ofthe con-' tact fromthe respectively associated recesses. Thus, the two parts of theconnector device are adapted to separate when a disengaging force isapplied to the associated conductor in any angular or lateral directiongenerally away r from the socket or outlet receiving the adapter. Itshould be apparent that other arrangements are possible for establishingreadily disengageable electrical contact between the two elementscomprising the conductor without departing from the spirit of theinvention.

In FIGS. 56, there is shown a modification of the attachment embodimentof FIGS. 1-2. The modified attachment indicated generally by the numeral14a is shown to comprise a casing 34a made from a material similar tothe casing 34 and including a third face 36a. Included within the casing34a is at least one contacting element 44a but preferably, and as shown,two contacting elements 44a, 44a are provided. Each of the contactingelements includes a contact 46a projecting from the face 36a. A magnet48a is disposed within the casing 34a proximate the face 36a. It will benoted that in all of the foregoing respects the connector attachment 14ais substantially identical to the connector attachment 14 previouslydescribed.

However, the attachment 14a of the modified form differs from thepreviously described attachment 14 in that the casing 34a preferablydefines a cavity or annular recess 50 wherein direct electricalconnection with the conductor is made.

Each of the conducting elements 44a includes a terminal end 52 disposedwithin the recess 50 and as shown is turned radially outwardly therein.Each of the terminal ends 52, 52 is preferably threaded to receive aterminal screw 54 for establishing electrical connection with anelectrical conductor 16a. An opening 55 within the side of the casing34a communicates with the annular recess 50 and receives the electricalconductor 16a. Thus, when the conductor is secured to the associatedterminal ends 52, 52, a path of electrical current is provided betweenthe conductor and the contacts 46a, 46a. A cover 56 engaging the casing34a and secured thereto by a threaded fastener 58 provides a closure forthe recess 50 to prevent accidental contact with the terminal ends.

The invention claimed is:

1. An electrical connector for providing a breakaway electrical couplingbetween a conductor and a socket having a receptacle, said connectorcomprising a first component having a male element adapted to bereceived in the receptacle to establish electrical connection with thesocket, a second component adapted for electrical connection to theconductor, said first component and said second component being mutuallyengageable, conductive means for providing a path of electrical currentbetween said male element and the conductor when said components areengaged and separate securing means for maintaining engagement betweensaid components, said separate securing means being adapted to permitsaid components to mutually separate when a disengaging force is appliedto the conductor in any direction generally away from the socket, andsaid separate securing means being adapted to separate under theinfluence of a disengaging force substantially less than the forcenecessary to separate said male element from the receptacle.

2. The combination defined in claim 1 wherein said conductive meanscomprises at least one conducting element associated with one componentand having a terminal disposed within a recess defined by said onecomponent, and a contacting element associated with the other componentand having a contact outwardly projecting from said other component,said contact being received within said recess and engaging saidterminal when said components are engaged.

3. The combination defined in claim 2 further characterized by said onecomponent having at least one face, and said recess opening through saidface and generally diverging thereto, at least a portion of said contactgenerally complementing an associated portion of said recess.

4. The combination defined in claim 1 wherein said separate securingmeans comprises two magnets, one of said magnets being associated withsaid first component and the other of said magnets being associated withsaid second component, said magnets being magnetically coupled tomaintain engagement between said first component and said secondcomponent.

5. The combination defined in claim 1 wherein said separate securingmeans comprises at least one magnet associated with one of saidcomponents, and a piece of paramagnetic material associated with theother of the said components, said magnet being arranged to magneticallyattract said paramagnetic material for maintaining engagement betweensaid adapter and said conductor attachment.

6. The combination defined in claim 1 wherein said separate securingmeans comprises two magnets, one of said magnets being associated withsaid first component and the other of said magnet being associated withsaid second component, said magnets being so arranged that the magneticfields thereof coact to produce a condition of mutual magneticattraction in a first angular position of the first component relativeto the second component and a condition of mutual magnetic repulsion ina second angular position of the first component relative to the secondcomponent, whereby said components are maintained in engagement in saidfirst position only.

7. The combination defined in claim 1 wherein the electrical conductorincludes a plugging element, said combination further characterized bysaid second component defining at least one receptacle for receiving theplugging element.

8. The combination defined in claim 1 further characterized by fastenermeans associated with said second component for electrically connectingthe conductor theret0.

9. In a breakaway electrical connector for coupling a flexibleelectrical conductor with a conventional electrical socket element, saidconnector comprising a male adapter having a magnetically permeableelectrically nonconductive housing including a first face and a secondface, said first face having therein defined at least one socket recessgenerally diverging to said first face, at least one conducting element,said conducting element having a terminal disposed within said recessand including a prong projecting outwardly from said second face forengaging the socket element to establish electrical connectiontherewith, an attachment having a magnetically permeable electricallynonconductive casing including a third face, at least one contactingelement adapted for electrical connection to the conductor, saidcontacting element including a contact projecting from said third face,said adapter and said attachment being engageable with said third facein close proximity to said first face and with said contact engagingsaid terminal within said recess, and connecting means for maintainingengagement between said connector and said attachment, said connectingmeans being adapted to permit said connector and said attachment toseparate when a disengaging force is applied to the conductor in anydirection generally away from the socket element and said connectingmeans being adapted to separate under the influence of a disengagingforce substantially less than the force necessary to separate said prongfrom the socket element.

10. The combination defined in claim 9 wherein said connecting meanscomprises a first magnet disposed within said housing proximate saidfirst face, and a second magnet disposed within said casing proximatesaid third face, said magnets being so arranged that the magnetic fieldsthereof coact to produce a condition of mutual magnetic attraction in atleast one angular position of said attachment relative to saidconnector.

11. The combination defined in claim 9 wherein the electrical conductorincludes a plugging element, said combination further characterized bysaid casing including a fourth face and defining at least one receptacleopening therethrough for receiving said plugging element, at least aportion of said contacting element being disposed within ReferencesCited said receptacle for establishing electrical contact with theUNITED STATES PATENTS plugging element. n

The conbination defined in e 3 a 31335;??? iii???3322?-1Ii131113'555i333fi acterized by said casing definlng a cavlty,said contacnng 5 element including a terminal end disposed Within said iFOREIGN PATENTS cavity, fastener means associated with said end forelec- 128,831 9/1948 Australia.

trically connecting said conductor thereto, and a cover engaging saidcasing and secured thereto providing a clo- MARVIN CHAMPION, PrimaryExaminersure for said cavity. PATRICK A. CLIFFORD, Examiner.

